


It's Okay, Sweetheart

by MindscapeWish



Category: Gravity Falls
Genre: Bottom Dipper Pines, Deer Dipper Pines, Dom Dipper Pines, Fluff and Smut, M/M, Mating Cycles/In Heat, Naga Bill Cipher, Predator/Prey Dynamics, Some masochism, Sub Bill Cipher, Top Bill Cipher, dealing with trauma aftermaths, full of dipper loving scared bill, shapeshifter Dipper Pines
Language: English
Status: Completed
Published: 2021-02-14
Updated: 2021-02-14
Packaged: 2021-03-14 12:22:23
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,264
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29418594
Author URL: https://archiveofourown.org/users/MindscapeWish/pseuds/MindscapeWish
Summary: Bill, an escaped ex-captive naga, has finally settled down with his beloved boyfriend, Dipper. However, his mating season has finally arrived and he fights with the past and with his instincts.Or:Bill is horny as hell and uncomfortable. Dipper understands and offers to help. In the midst of tooth rotting, heart warming fluff, Bill finds physical and mental relief in making love with Dipper. Truly half fluff and half smut.
Relationships: Bill Cipher/Dipper Pines
Comments: 6
Kudos: 57





	It's Okay, Sweetheart

Bill adjusted his position on the couch for the 7th time in the ten minutes he’d been sitting with Dipper on the couch. His skin itched, _crawled_ even. In fact, he had been antsy and fidgety for quite a few days, but only today it had struck its worst. Bill was positive that Dipper had noticed by now, but he could hold it back.

Spring had crept in after the long, cold, sleepy winter where Bill spent his days in blankets and napping, and settled down into the month of April. And, well…

He was horny. There, Bill admitted it. Bill was unbelievably horny for the first time in several years, something he was not accustomed to in the slightest, and everything told him to press Dipper down into the bed, flip him over, and shove his dick (maybe _both_ ) inside of him.

God. Just the _idea_ of the image of Dipper beneath him, featured scrunched in blissful pleasure, was enough to send blood rushing down towards his dick. Bill stifled a whine and shifted his hips away from Dipper’s line of sight.

Just as Dipper stretched out long, yawning and draping his legs over Bill’s lap.

Shit. Shit, shit, shit, this was bad. Bill pulled his legs up instantly, cheeks a permanent state of red. Out of the corner of his eye, he saw Dipper give him an odd look.

"Bill, are you okay?"

Thank god that Bill barely took his mask off. The soft, black fabric meant to block out scent was able to conceal his flushed cheeks too.

“Y-Yeah! I’m fine, why?”

“You’re acting weird.” Dipper frowned, concern in his eyes, and sat up. He pulled his legs back from where they flopped and raised his hands slowly. Bill was still a predator, still wary of fast movements, still adapting to a life where he wouldn’t be punished, so it was only fair to be cautious. If Bill didn’t want Dipper to touch him, he could object if he wanted.

Bill’s eyes locked onto Dipper’s hands, pupils narrowing and body tensing. The naga didn’t object though; Dipper, for the near-year Bill had been there, was nothing but gentle.

Dipper cupped Bill’s cheeks and pressed his inner wrist to Bill’s forehead. A shock of heat panged inside Bill’s belly the instant he felt Dipper’s touch.

“You don’t feel warm…” Dipper pursed his lips. Bill had a naturally lower temperature considered he was more cold blooded than anything, but the sun, lamp, and blankets he’d been preoccupied with before kept him warm enough to function-- yet, he didn’t feel sick.

Bill ducked away from Dipper as soon as possible. “I’m completely fine!” he stammered, much too quickly. “Yeah, don’t worry about it.”

 _Fuck_ these jeans, goddamn it. They showed everything and the stiffy in his pants was only going up, not down. Bill shouldn’t have chosen this fucking human form for today.

Dipper looked over Bill's body, still frowning and attempting to figure out what was wrong. Bill never acted this nervous, nor did he curl up like that. Prey animals did that while in a nervous or scared state, never predators. So what gives?

Bill felt himself be scrutinized. He didn’t like that.

He noticed how Bill’s position was horribly awkward. It wasn’t uncommon for him to twist himself into weird positions, given his mobility and flexibility that matched his species, but this wasn’t one of them. He tilted his hips away from Dipper and scrunched himself up, arms covering his lap. Bill obviously felt scrutinized, based on the minor bristling.

Wait. Bill wasn’t letting himself be touched either, not for the past few days. Any clothing that hugged him was shucked “because his skin was sensitive” even though Bill never had a problem with it before. He was keeping his distance away from Dipper, even in bed when they were going to sleep, yet Dipper woke up with Bill’s hips against his thigh. Combining these with the fact that it was spring and Bill indeed _was_ an animal…

“Do snakes have mating seasons?” Dipper hesitantly asked.

This time, even Bill’s neck and the tips of his slightly pointed ears turned a dark red on his darkly tanned skin. _Fuck._ Dipper caught him. He shrunk back into the corner of the couch, glancing away in shame, and weakly nodded. “Yeah,” he said softly.

This was humiliating. Utterly humiliating. Not only was Dipper aware that Bill was wanting to get into his pants this entire week, which in itself was embarrassing and potential grounds for insecurity for many reasons, but… Bill felt disgusting. He could not control it, and he knew that he shouldn’t blame himself, but he still felt gross. Bill felt like he was just some animal ( _because he was treated like one for more than half of his life_ ) that had to be supervised because he didn’t have the power to overcome this, just like a slave to nature.

He felt gross too because he had urges like this and he never got to indulge in it. _They_ had seen it as a taboo, making him ashamed that he even experiences sexual things, even though he is an animal, has needs, and is an adult. He shouldn’t need this. He shouldn’t _want_ it, more importantly.

Dipper's expression softened-- even perked up in a quiet, amused laugh, but not mocking. He tilted his head and softened his voice. "And I'm guessing you're worked up?" 

Bill avoided eye contact as much as possible. Dipper was gentle and sweet with him, not jeering, but he felt like he didn’t deserve the comfort.

"Yeah…” he murmured after a few long moments. “But it's not your problem, so don't worry about it." Bill was the bottom in the relationship and having it switched seemed weird, plus Dipper wouldn't like it, would he? Dipper never expressed any interest in wanting to bottom for him, so Bill wasn't going to ask. That wouldn’t be fair to put him into an uncomfortable position just because Bill needed to get off.

"It's not my problem, but you're my partner," Dipper replied. He reached for Bill's hands and held them in his own when they were given. He rubbed his thumbs against the back of his love’s hands in long, soothing strokes. "Can you look at me?"

Could Bill? Just mustering up a reply to anything Dipper said to him felt like lugging hundred pound boulders. The guilt and shame bubbled up in his throat and pressed down on his chest suffocatingly.

Bill hesitantly did as he was asked, blue and gold eyes meeting with Dipper's. They were the most comforting, cozy dark brown that he'd ever seen. Looking into those eyes made him feel like home.

Bill didn’t want this, but as long as Dipper was with him, as long as Dipper loved him, he began to think that maybe it’d be okay.

"If you need me to, I'd be happy to help you out," Dipper said earnestly. "I don't want to let you suffer here. I'd be into it too, so if you need it..."

Bill blinked. Relief flooded his body. God, this was a reason why he loved Dipper so much. Not the sex, but the genuine care that he had for him. Bill was never second priority and he was never ignored or cast aside. Dipper made him feel whole and important for once in a very, very long time.

"I... If you're okay with it... tonight?"

Dipper smiled at him, a smile that Bill could never see without melting, and kissed his forehead lovingly. "Of course. Whenever you want to, I'll be ready."

Bill swore his heart would rip out of his chest from how fast it beat. From how hard it clenched, just to be looked at with as much love and importance as Dipper did. There was not a doubt in his mind that he would never let this boy go.

Dipper pulled away to give Bill his space and settled into the opposite corner of the couch. They didn’t have to talk any more about it now, but just simply relax. At some point, Bill moved so his head was on Dipper’s lap, but that was the extent of their physical interaction.

When the night came, darkness falling upon the little house in the middle of the woods, they both kept their promises.

The bed was almost discouraging when looking at it empty, as if it screamed how humiliating this entire season was, but seeing Dipper stretch out on it and gently encourage him with grabby hands eased Bill’s initial anxieties. Dipper wanted Bill just as much as Bill wanted him, and that made things all the better.

When Bill joined Dipper in bed, they didn’t do too much straight off the bat. Dipper removed Bill’s mask with enough tenderness to make the naga want to cry, heart throbbing with something he couldn’t name. Their lips met in soft, warm kisses that warmed their bodies from the top down, limbs tangling together. Bill reached out to pull his lover close to his body as if it were his last day on earth and Dipper wrapped his arms around him, their chests meeting. Bill swore that Dipper would be able to feel his heartbeat from how fast it raced.

“You can relax, sweetheart,” Dipper murmured into the space between them. He shivered as Bill’s fingertips brushed against his bare back where his shirt rode up. “Nothing’s gonna happen that you don’t want to.” 

To his words, the naga’s muscles beneath Dipper’s hands drained of their tension. He smiled.

“I trust you,” Bill whispered. He pressed forward in another kiss, pouring all that he could from his little heart into it. Dipper’s hands caressing his sides and hips brought goosebumps to his skin and he wanted more-- to be for him entirely, wrapped up and protected by this little deer shifter that had turned his life around from abuse and servitude to happiness and unconditional love.

Time had no place in their bedroom. Whether it was seconds, minutes, or hours that passed while they kissed and tasted each other, tongues brushing and skin warming under light touches, neither of them kept track. All that they knew for a sense of passing time was that they were panting into each other’s mouths before they even took their clothes off.

Bill was the first to initiate it. When he pulled away from the kiss, a string of saliva broke between their lips that was oddly arousing. He suppressed a shiver and instead swallowed. It took courage to twist his limbs out from around Dipper’s and climb on top of him.

Dipper said nothing, allowing Bill to take this at the pace he wanted, but he peered up at him curiously. The red blush on his pale cheeks was truly a sight to behold.

Bill looked down at Dipper’s maroon flannel, wrinkled and pushed up from their make out session. The soft, smooth skin of his stomach was exposed, wisps of a happy trail below his belly button. He was used to pushing down his instincts and desires, but right now, he let himself long to follow that trail down and that path of skin up with his tongue. Gingerly, Bill unbuttoned Dipper’s shirt one by one and opened it up to expose the rest of his torso.

Dipper noticed how Bill licked his lips and shivered. He actually found himself forgetting their species’ dynamic, predator and prey, way too often. He couldn’t be upset about it though because the very reason he forgot was that they went _against_ it most of the time. Dipper was by nature a skittish deer, but he took the daring initiative. The naga on top of him could unhinge his jaw and swallow Dipper right up, but instead, he looked so mouseish and small.

“Like what you see?” Dipper grinned up at him. Bill’s fingers twitched, aching to touch him. Dipper had to physically lead Bill’s hands to his chest and say “You can feel me, it’s alright” to get him to shake those nerves off.

It was… peculiar, to be honest. Bill was the one in mating season here and Dipper was prepared for him to jump his bones instantly, but instead, he’s taking it slow and reluctant. Overall, _patient._

Bill cupped Dipper’s neck and caressed his skin, taking everything about Dipper in and memorizing it like he’d never see it again. He categorized every little thing and greedily stored it away-- how Dipper’s breast rose and fell in each long, calm breath, how his heartbeat raced and gave his anticipation away, how his ribs curved and dipped, stomach toned just enough to prove athleticism.

Bill didn’t mean to stare, but he did. Dipper was beautiful and Bill’s heart throbbed in his chest for him.

( _He didn’t want to ruin Dipper’s magnificence._ )

Bill leaned down and swiftly captured Dipper’s lips with newfound vigor and passion. He couldn’t say anything meaningful enough with words, anything that added up to the level of adoration he had for his partner, and all he could do was kiss him and hope he understood. 

Dipper understood. He made a noise of surprise, but certainly didn’t protest. Instead, he wrapped one arm tight around Bill and brought the other hand up to his hair, blonde and messy.

They came up for air and Bill took that chance to finally push Dipper’s flannel entirely off. It fell to the floor near their bed. It came to his attention that now he was fully clothed, whereas Dipper was half naked.

Dipper hummed and rubbed his hands down Bill’s sides. He felt the naga shiver beneath his touch. “You should take this off, my pretty boy,” he crooned. “Go ahead, it’s alright.”

Bill obeyed and tossed it with Dipper’s flannel without protest.

Bit by bit, they pulled each other’s bottoms and underwear off in between kisses and hot whispers. Now they both had access to every part of their bodies to adore, love, touch, stroke--

Except for one thing. One part, at least.

Bill had to pull away fully so that Dipper wouldn’t be crushed, something that he half-heartedly lamented because he wanted to be as close as possible to him.

Mating season couldn’t properly happen, or at least his urges could not be satisfied, until he was in the form that the season belonged to.

That is to say, Dipper had a very human looking boyfriend sitting on the edge of his bed one moment, and then a boyfriend with a 20-foot shimmering golden snake tail the next.

Bill always told Dipper how beautiful his deer form was, but Dipper truly thought that Bill rivaled him in every sense. It was the way black scales along the seam between his human and snake half blended out into gold, and afterwards showed up like freckles. Smooth, cool scales didn’t just cover his tail, but also came in smatters on his knuckles and cheek bones, his elbows and jaw. Dipper almost expected for the tips of Bill’s pointed ears to be scaled as well, but they weren’t. The scales scattered alongside his jaw led one’s gaze to his beautiful lips where fangs full of deadly venom ready to drip resided, but never even close to harmed Dipper. That forked tongue frequently poked out in ‘sssss’s, tasting the air on instinct.

What Bill would never find beautiful that Dipper found unique to him was the deep scar below his hip. When he was in his human form, it was in his left thigh. It left behind brownish grey, malformed scales and scar tissue from when he had been shot when he was young that healed wrong and mangled. It always ached when it got cold and Dipper helped Bill when it acted up.

“I bet that feels good,” Dipper remarked.

“It does.” The words came out in a groan as Bill laid back on the bed and stretched out his tail. It felt like standing up for the first time in a long time.

Dipper found that Bill’s beauty didn’t only reside in his tail, of course. It was in every little scar that knicked up his torso and in his cheeks, jaw, the arch of his fingers and strong muscles flexing beneath his skin. He wanted to do nothing but touch and taste every part of him now.

Bill quickly returned to kissing his partner when he no longer cramped up. Coils of tail wrapped around Dipper’s body and pressed their bodies close. Dipper’s erection was pinned against Bill’s hip, but neither of them gave it any particular mind. Taking their time to touch, feel, heat the other’s body up until they whimpered for more, was important to the couple.

Dipper traced the sensitive scales along the seam of Bill’s halves and Bill rubbed Dipper’s inner thighs, letting his nails trail across them. Dipper moaned and allowed a hot, forked tongue into his mouth. Bill massaged the globes of Dipper’s ass as Dipper sucked a bruise into his throat.

More time passed by without either of them noticing. Their breaths came out in soft pants and shared moans, kissing deep and long with hands rubbing chests, sides, hips… To feel the other arch up into their touch was something to treasure.

It came to a point where Dipper wanted to continue on instead of the prolonged foreplay. If Bill wasn’t comfortable with that, he’d tell him.

Dipper broke away from their kiss. Bill gave a soft whine because of the separation, but eagerly quieted down when Dipper began to move.

Dipper rolled them so he was on top and shifted back, straddling Bill’s tail, so he could get where he wanted. He looked down to Bill's tail, right in the middle below his hips where his (human-form) crotch would be if it were lower down.

There was a noticeable bulge that had formed as Bill became aroused with all their touching and feeling. Dipper had felt it before, but didn’t bring attention to it unless Bill had asked. The slit that his cocks laid beneath was stretching apart due to how hard he was. The scales that covered this part of Bill were much more sensitive and soft.

Dipper knew Bill’s body like the back of his hand at this point. He took his thumb and stroked the slit gently. Bill jolted in a gasped, hitched breath above him. Dipper smiled in victory and used the other thumb to part his slit completely.

Bill whimpered in pleasure, tail squeezing around Dipper. _Fucking hell._ He’d been touched like this before-- only by Dipper, he only trusted Dipper, and his Pinetree took such good care of him-- but right now he felt like a complete virgin. Breeding season truly ran his instincts wild.

"D-Dipper, fuck... F-Feels wonderful..." 

An immense sensation of pride built up in Dipper’s chest and warmed it. _He_ was the one making Bill feel so ‘wonderful’ and no one else, and he did his job _well._ Bill only deserved the best and Dipper himself was able to live up to it, at least for this night. If he were able to purr, he’d be the cat who caught the canary.

Dipper took his index and middle finger and slowly pressed them inside of Bill’s slit. It was hot and slick inside, but crowded with the cocks tucked away neatly inside. Bill clamped down around him with a louder moan and he smirked. With a little upwards coaxing, two cocks came sliding out of the slit single file.

They were huge. In a vertical pair, they stood thick, smooth, and already streaming with precum. Dipper still didn’t understand how Bill could keep them inside of him so comfortably and look flat from the outside.

“Damn…” Dipper let out a breath. The poor naga appeared the most turned on he’d ever been in his life. “I don’t think I can take both of them, Bill.” Dipper had never bottomed before and he was nowhere near mentally ready for two inside.

He grasped the bottom cock in his hand and stroked it with a tight grip. Bill’s hips thrust up into it instantly.

"Don't have to," Bill gasped, eyes rolling back. God, he ached horribly. He wanted to pound Dipper so fucking hard into the mattress that they both saw stars, that _maybe_ he’d knock the brunette up despite their incompatability, but every touch Dipper gave him rendered him a complete sub. 

Bill listened to Dipper chuckle to his responses above him.

"Would you rather I ride this bad boy or do you want to do the job yourself?" Dipper purred close to his ear, speeding up his hand. Bill’s body trembled and flexed beneath his touch, absolutely _deliciously._ He wanted to make Bill feel even better, to be so thrown in pleasure that he couldn’t think anymore. Dipper took the other cock with his free hand and jacked it to the same rhythm.

"I-I don't know." Bill's instincts told him to rail Dipper senseless but the shapeshifter's touch shoved him into a deep subspace every time. It wasn’t _just_ being Dipper’s sub that made him hesitate, but he didn’t want to admit that to himself. He didn’t want to admit that he was afraid of his first proper breeding season.

Dipper hummed softly to the answer. "We can take it slow so you can make up your mind, baby boy. Is there something you want me to do?"

God, that _nickname._ Bill shivered every single time Dipper called him it. He felt so safe, so loved, so _wanted_ when Dipper gave him that name. It ached in a way that his heart almost hurt from the intensity, but his cocks were more excited than ever.

Bill peeled his eyes open and he nodded, biting his bottom lip between his teeth. He reached a shaking hand out for Dipper’s cock to stroke him too.

“Jus--Just continue.” He swallowed, then added, “Kiss me?”

Dipper’s eyes crinkled. Bill swore he could cry from how loving Dipper looked at him.

"Of course."

They fell into each other, their hands pumping each other’s dicks and lips locking deep just like before. There was no hurry or push for Bill to make up his mind. There was no urgency or beckon towards a specific choice… Just understanding, love, and adoration.

Bill’s touch made Dipper’s skin tingle in the best of ways, almost as if all his nerves lit up in attention for him. Dipper was protected by his amazing boyfriend, yet wasn’t doubted to protect Bill in the same way. 

Dipper’s touch made Bill calm and off guard, showing him safety and unconditional love. It relaxed the muscles that were tight from years without release and embraced the confidence of being in his own skin, a special kind of acceptance. A special kind of healing.

Bill whined against Dipper’s lips, breath coming out in shaky huffs. Precum dripped down the undersides of his cocks, just to be swiped up and spread by Dipper’s wonderful hands. He had to keep himself from bucking up so Dipper wasn’t jostled in his spot.

Dipper sighed in relief as Bill pumped him nice and quick. They had been bumping and grinding before, but he was never touched until now. “Mmmugh…”

Bill still wasn’t quite satisfied, though. Dipper’s hands made him squirm, but his itch still wasn’t scratched-- his instincts bubbled up, begging to sink his cocks into Dipper’s ass and have his way with him.

Maybe… Maybe doing that wouldn’t be too bad. It would be okay, wouldn’t it? He’d be in control, Dipper was great at communication, and everything would be okay.

Bill pulled away from their kiss. Their lips smacked with an echoing pop. "Could I be on top this time?"

Dipper looked up, and without a second’s hesitance, smiled. He slid his hands off of Bill. “I don’t see any problem with that.” He was expecting Bill to want to take the role as top, considering the nature of how breeding seasons went. All Bill had to do was say something.

He swung his leg over Bill’s tail so he was no longer straddling it, though he was caught up and tangled in the rest of it. Bill _did_ love to keep him close and secure. The thought of that made Dipper’s heart throb as he laid back in the sheets.

Bill got on top of Dipper and slipped his hips between his legs, forearms on either side of his lover’s head. From here, it was clear they were both flushed to hell and back. There might be more blood in their cheeks and dicks than their brains at this point.

Dipper got one look at Bill on top of him and a whole new feeling flooded his system. Bill looked so powerful above him, muscles tensing and moving with very clear power in all of him. Bill could squeeze his tail and suffocate Dipper right there, he could do whatever he wanted, and yet he was looking like he was afraid of Dipper breaking.

He was so beautiful. Dipper had thought it a billion times already, but he could never _not_ be in awe of him. Bill below him was taming the beast, beautiful and writhing, but this was being dominated for once and Dipper craved it. The intense need filling his body was nearly blinding.

Dipper parted his legs further and grabbed the lube. "God, I need you so bad. Fuck me as hard as you want, baby, I know you want to and I want it too." He covered his fingers in lube and slipped them down to quickly prep himself. (He didn't trust those talons inside of him.)

Bill, on the other hand, was reeling from how Dipper looked beneath him. Dipper always had a strong, dominant attitude in bed, keeping his rightful place on top of him and having fun. Now he was willingly submitting, curly hair splaying in the pillows below him, legs parted so pretty, cheeks such a soft red. Bill's heart pumped faster, cocks producing pre-cum beading at the tips.

"I love you so much… god," he whispered, completely breathless. Bill watched Dipper's expression go from twisted and uncomfortable from the new, unusual intrusion, to melting into pleasure and bliss as he fingered himself. His eyebrows pinched, lips parting in soft pants.

Bill had never wanted to fuck Dipper so bad as he did in this moment.

"I-I love you too," Dipper grunted, arching as pleasure tingled up his spine. His toes curled, breathing out moans, as he scissored himself as open as much as he could. Dipper had four fingers in to take Bill's size, but even then it was barely enough. There was no way he could take both of Bill’s cocks when he could barely take one as it was.

Dipper knew he was ready to go when his impatience made his skin itch and crawl. He practically drooled in excitement.

“I’m ready.” Dipper wrapped his arms around Bill's neck and pulled him in close, their foreheads touching. They were both ready to go with equal vigor, equal desire, and now they didn’t have to wait anymore.

Bill didn’t have to be miserable anymore.

Bill reached down and positioned himself so the head of his lowest cock was pressed against Dipper’s entrance. Dipper’s hole quivered against it and their breaths hitched.

"Tell me if you need me to stop, okay?" Bill murmured. He hoped they didn't have to stop. He was so close to scratching the itch he'd had for so long-- so close in getting relief.

His fear and reluctance remained, but the promise of being free of discomfort was enough to drown them out for a little bit.

"I will. Don't worry, sweetheart." Dipper smiled and kissed Bill's head. His beloved partner needed this, more particularly from someone he trusted. Plus, Bill had helped Dipper through his own mating season during the Fall before-- it was only fair if they were both into his.

Plus… Dipper _did_ wonder what bottoming would be like. He preferred to be in control of the situation, but those lithe, flexing muscles, those cocks, Bill’s power… It was much too tempting and delicious to resist.

Bill searched Dipper’s eyes for a few moments in hesitance. He worried, but he trusted Dipper with everything he had. Dipper would tell him if he needed to stop and Dipper wouldn’t… _use_ him. With a little nod, Bill began.

Inch by inch, Bill steadily sheathed himself inside of Dipper. It was a very new sensation for the both of them-- stretching Dipper out so much, the heat of his insides, the second cock gliding along Dipper's abdomen and slotting against his dick.

Bill watched Dipper's mouth part in a silent gasp, stunned, and Dipper saw how Bill's eyes rolled back in pleasure. Their choked moans entangled together in the air. Both were total wrecks already and they'd barely even started.

Bill had to stop when he was as far inside Dipper as he could possibly be without hurting him. It was as if there was a block there, barring him from continuing.

When he looked down to where they were joined, he could fucking _see_ himself in Dipper's abdomen. There was a perfect bulge in the beautiful, creamy skin in the shape of his cock. " _Oh god._ " His cocks twitched from the sight and the bulge did too inside of Dipper.

Dipper was fucking speechless. That's it, he was ruined for everyone forever-- for even himself. Bill filled every part of him, pressed up against his walls and his prostate, making him feel like a whore taking two at once. There was no explaining how deep into blinding ecstasy he was.

"M-Move," Dipper demanded, twitching his hips up against Bill. He was huge, it hurt, but he was okay and it'd never get better until he started moving.

Bill did as he was told with no protest whatsoever. Now that he got a taste, he didn’t think he’d be able to deny himself it again. Bill pulled back enough that he couldn't see himself anymore and pressed slowly back in. His breath caught.

"Faster, baby, I can see you're holding back," Dipper moaned out, nails digging into Bill's back. "I'm not fragile, go ahead. Fuck me senseless.” Then, a whisper in Bill’s ear, “Fuck me full of your eggs.”

Bill was stunned that Dipper knew _anything_ about eggs because he never mentioned it-- but that was Bill's cue to, to put it simply, go nuts (pun not intended), and any thought outside of railing his ass vaporized. Dipper had given him the okay to do what he needed, what he craved, and he'd take it.

In a split second, Bill _slammed_ his cock in and out of Dipper’s ass in jolting, sharp snaps that brought most of him out of Dipper, then plunged all the way back inside of him. He couldn't stop, didn't _want_ to stop, because the relief filled him farther with every slam inside. The itch was finally being scratched. 

His claws dug into the bed so much that the sheets wore thin from the sharpness cutting at the material. His lips pulled back to expose sharp, siren-like teeth in growled moans and pants.

Dipper _wailed_ as he was plowed into the bed so damn good. His brains would be fucked out of his head by the end of this. Dipper scratched up Bill's back for purchase, body rocked and bed creaking dangerously with every thrust. 

"F-Fuck fuck _fuck_ Bill! Bill oh my god harder!" He could barely choke out the words, mouth opened in permanent drooling babbles and cries. If this was what bottoming was like all the time, he’d ask Bill to take him more often, because _holy shit_ he could barely see anything that wasn’t stars.

How could Bill ever say no to that?

Bill bunched Dipper up so much that his ankles nearly met his ears, the second cock rubbing up against Dipper's so damn good. Their precum mixed and smeared, making the slides slicker. 

_Breed him, fuck him full!_

Bill’s jaws parted and he latched onto Dipper's shoulder, biting hard down into him for purchase.

Dipper screamed in pained-pleasure as Bill sank his fangs deep into his skin. He should be fucking terrified but he wasn't, -- he couldn't feel any venom, but even if there was, right now it would have been hot-- caught up in the pain and how it went straight down to his cock. A familiar pressure built up in his groin so quickly that he nearly had whiplash.

"I'm gonna cum gonna cum gonnacum! Please!" he sobbed. "Fuck me, baby boy, fuck me good-- make your Master cum, c'mon, do it!"

Bill could only slam in harder, growling loud. Even when he was on top, Dipper never failed to get him controlled, and _jesus christ,_ now it was even hotter.

They were animals in species and animals in bed too.

One thrust, two, three, a fourth and both of them cried out in the hardest orgasms in a while. Cum spilled all over Dipper's stomach and flooded Dipper's insides. Bill tightened around him like a constrictor and Dipper could barely breathe, but the suffocation feeling only added to the ecstasy.

Dipper’s vision blacked out momentarily right as Bill’s head dropped down against his shoulder.

Several minutes passed by, both of them completely still. Neither of them said a word, so caught up in each other that they couldn’t unwind individual thoughts for their individual tongues. Their skin stuck together in sweat, bodies trembling, catching breath. They were fucking exhausted, surprised, relieved, worn out, all of it.

Bill carefully pulled out and eased Dipper’s legs down, minding the soft grunted whine he was given. The incessant demand that had been nagging him in the back of his mind for so long finally ceased and his instincts sated.

“Are you okay?” he murmured.

Dipper swallowed and nodded. “Yeah. Are you?” he whispered in return. He couldn’t move at all, but he was okay. His ass stung and his thighs, hips, and knees ached like hell.

He wouldn't trade it for the world though.

Bill bit his lip and chuckled. It was always a Dipper thing to do… Make sure he was alright. Dipper was the one with the naga dick up his ass, yet he still fussed over Bill.

“Yeah. I’m great.” He nuzzled their noses together, foreheads pressed together again. Dipper’s giggles lit up his heart, filled him with enough love that it hurt horribly.

“Well…” Dipper played with Bill’s hair, fingers pulling at the wisps and twirling them. He brushed it all out of his eyes. “How do you feel?”

“So much better.” Bill eased them to their sides so their muscles could take the break they needed. “I…” He fell quiet, eyes glazing in thought.

Dipper patiently waited. Meanwhile, he continued to cup Bill’s cheeks, stroke them, love on the scales patching his skin.

“That was…” Bill didn’t know how to admit it. He should quit while he was ahead, if only to spare his energy putting things to words. But he continued on. “That was my first mating season.”

Dipper’s brows furrowed together in confusion. He tilted his head. “What do you mean? I thought sexual maturity in nagas was about 13.”

Bill avoided Dipper’s eye contact and he nodded, choosing to stare at the other’s collarbones. “Well, um… Yeah. It is. But… My first one was really bad, so I don’t quite… count it, or think of it. And then I wasn’t allowed my tail, so… I couldn’t have any proper seasons until now.”

He and Dipper had just released the bindings his captors kept on him a few months ago. Mating season couldn’t happen without the proper parts and he’d been denied them for all of his formative years.

Dipper’s heart throbbed in the painful way. Bill had told him a lot of what… _they_ did to him, but some things were still kept secret. It was understandable and Dipper wouldn’t push him… It just hurt him that someone he loved so much had been hurt so badly.

If this was his first mating season, then Dipper was more than honored to be allowed to share it with him.

“Do you want to talk about it?” he asked gingerly. Bill shook his head.

“No. I just wanted to thank you.”

They smiled tiredly and shared a gentle kiss. Nothing else needed to be said because the understanding was already there. They loved each other and were more than happy to experience this together, for both shared and individual reasons.

Their clean up was slow. Neither of them wanted to get out of bed, but at least one of them needed to in order to grab a wet rag. Bill ended up being that person since Dipper was so wrecked and initiated the careful, tender aftercare process.

Bill tucked himself back into his slit after cleaning his cocks and wiped the cum off of Dipper’s stomach and thighs. Dipper’s muscles rippled beneath his touch in sensitivity and focus.

Once they found themselves clean enough for tonight, they both wrapped themselves up in the other and fell fast asleep in the blankets. Their limbs tangled, hearts beating in the same rhythm.

They fell asleep with each other's tastes on their tongues.

They fell asleep with:

“I love you,” in a soft, high voice.

“I love you too, sweetheart,” in a voice that would never get tired of saying it.

**Author's Note:**

> Happy Valentine's Day, everyone! This technically wasn't for the holiday, but I finished it in time, so here you go.
> 
> This is for my wonderful RP partner, Leo. I wrote this prompt out for our Naga x Deer Shapeshifter AU back in October I believe and decided to flesh it out into a real one shot. In another work I wrote, I gave Naga Bill the name Viper, so that is why this is tagged like that. This is also technically part one of two, so please keep an eye out for the next part!
> 
> Please consider checking out my tumblr, mindscapewish-writes! Say hello, ask questions, whatever.
> 
> Let me know what you thought of this!
> 
> Thank you for reading!


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